netdev - Re: [PATCH 2/2] net: Implement SO_PASSCGROUP to enable passing cgroup path

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CALCETrVBJFgKwRKBE2jAG6kiGgkJ+MyQiw2nyz5yj0h68kCk9A@mail.gmail.com>
Date:	Thu, 17 Apr 2014 10:35:17 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Simo Sorce <ssorce@...hat.com>
Cc:	Vivek Goyal <vgoyal@...hat.com>,
	Daniel J Walsh <dwalsh@...hat.com>,
	David Miller <davem@...emloft.net>, Tejun Heo <tj@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	lpoetter@...hat.com, cgroups@...r.kernel.org, kay@...hat.com,
	Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH 2/2] net: Implement SO_PASSCGROUP to enable passing cgroup path

On Thu, Apr 17, 2014 at 10:33 AM, Simo Sorce <ssorce@...hat.com> wrote:
> On Thu, 2014-04-17 at 10:26 -0700, Andy Lutomirski wrote:
>>
>> Not really.  write(2) can't send SCM_CGROUP.  Callers of sendmsg(2)
>> who supply SCM_CGROUP are explicitly indicating that they want their
>> cgroup associated with that message.  Callers of write(2) and send(2)
>> are simply indicating that they have some bytes that they want to
>> shove into whatever's at the other end of the fd.
>
> But there is no attack vector that passes by tricking setuid binaries to
> write to pre-opened file descriptors on sendmsg(), and for the other
> cases (connected socket) journald can always cross check with
> SO_PEERCGROUP, so why do we care again ?

Because the proposed code does not do what I described, at least as
far I as I can tell.

--Andy




-- 
Andy Lutomirski
AMA Capital Management, LLC
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html